As if you needed a personal invitation from me, here it is nonetheless. Please join me (and a several thousand of your colleagues) at the American Hot Rod Association [ahem] American Healthcare Radiology Administrators annual meeting in August. And though it may not really be my place to invite you to the conference, I do want to extend to you a personal invitation to 2½ special events that will happen during that week.
‘NEWS FLASH: Large icebergs may present grave hazards to ocean liners.’
No, that’s not what the FDA just said, but the news in the FDA’s most recent alert is almost as dated as my hyperbolic example. What the FDA did in their March 5th alert on the MRI safety of transdermal medication patches was essentially … Click to find out what the FDA’s alert ‘essentially’ did…
As mentioned in an earlier post, noted MR safety guru Dr. Emanuel Kanal gave a brilliant presentation at the 2008 annual meeting of the American Healthcare Radiology Administrators (AHRA). While his session, “MR Safety Update, 2008” addressed several different MR safety issues, below is a video excerpt, which marries the audio recording with his presentation slides, showing information on ferromagnetic detection that Dr. Kanal presented.
Among the ACR Guidance Document on Safe MR Practices: 2007, the recent Joint Commission Sentinel Event Alert #38 on MRI Accidents and Injuries, and other standards and expert recommendations, it is abundantly clear that ferromagnetic detection is a potent part of an effective MR screening program.
A PDF transcript of the above video is available for download at http://MRImetaldetector.com/blog/wp-content/uploads/Transcript_of_Dr_Kanal_Edited_video.pdf.Tobias Gilk, President & MRI Safety Director Mednovus, Inc. Tobias.Gilk@Mednovus.com www.MEDNOVUS.com
In short, no. Hand-held magnets do not do the same job that ferromagnetic detectors do.
In many MRI facilities, foreign materials brought by people to the MR suite are tested for magnetic field hazards with high strength hand-held magnets. Ones designed specifically for MRI screening are far stronger than the ones holding up my daughter’s artwork on my refrigerator. Some of these ‘test’ magnets can be 1 Tesla at the surface (10,000 gauss)!
These extremely powerful hand-held magnets can help users differentiate between superficial materials that are, and are not, ferromagnetic, but the extraordinary strength of these magnets introduces a number of additional cautions which limit their use.
First, the key word in the paragraph above is ‘superficial.’ The magnetic field of all permanent magnets drops off precipitously (field strength drops with the cube of distance… double the distance and the magnetic field is cut to 1/8th the original value), so permanent magnets will be useful for distinguishing ferromagnetic materials only at or near the surface of an object. Ferromagnetic components below the surface may go undetected by a hand-held magnet, but rest assured that the MRI will find them if those objects make it into the scanner room!
Second, the potential forces exerted on a ferromagnetic body with magnetic field strengths of near 1 Tesla mean that shallow ferromagnetic material within the body of the patient could be moved, perhaps dangerously, by these very strong magnetic forces. But if the purpose of screening is to prevent accidents instead of preemptively causing them, hand-held magnets are poorly suited for patient screening.
Third, if screening medical equipment instead of patients, even some pieces of equipment designed for use in MRI scanner rooms have maximum allowable static and dynamic magnetic field values. Sticking a 1 Tesla magnet all over an anesthesia machine may wind up having some unintended consequences with regard to operation.
Lastly, 1-Tesla magnets stick hard to things. While the hand held magnets aren’t weighty, their magnetic force can require a bit of elbow-grease to get them separated from the cart or medical gas cylinder to which they got stuck. No, it’s not like it becomes epoxied on, but wielding one of these high strength permanent magnets is not a trivial affair.
Each ferromagnetic detection product has its own limitations, so I’m not attempting to state that FMD systems are the perfect solution to the hand-held magnet problem. Hand-held magnets can be useful, in a limited range of uses.
When it comes to the recommendations of the ACR Guidance Document for Safe MR Practices, or the Joint Commission Sentinel Event Alert (#38) on MRI Accidents and Injuries, or the U.S. Veterans Administration’s new MRI Design Guide, the experts all seem to have recognized the benefits of ferromagnetic detection and made a clear distinction between the new technology and the old custom of using permanent magnets to test for safety.Tobias Gilk, President & MRI Safety Director Mednovus, Inc. Tobias.Gilk@Mednovus.com www.MEDNOVUS.com
For those in the unenviable role of having to make tough decisions about which safety features to invest in and which to forgo, one key factor to these decisions is compliance.
For those administrators stuck between ‘legal liability’ and ‘budgetary constraints’, sometimes the decision of which safety improvement to invest in has a lot to do with who recommends (expects) it. Regulatory compliance is an imperfect litmus test of safety, to be sure, but like it or not, when the accrediting bodies speak, people listen. In the past year there has been a growing chorus of accrediting and regulating bodies that have all called for ferromagnetic detection in MRI patient screening.
Let’s start at the very beginning (“What a very good place to start.”), with last summer’s publication of the ACR Guidance Document for Safe MR Practices: 2007…
“[F]erromagnetic detection systems are currently available that are simple to operate, capable of detecting even very small ferromagnetic objects external to the patient, and now, for the first time, differentiating between ferromagnetic and nonferromagnetic materials. While the use of conventional metal detectors is not recommended, the use of ferromagnetic detection systems is recommended as an adjunct to thorough and conscientious screening of persons and devices approaching Zone IV.” [Emphasis mine.]
Just a few months later, the UK’s MHRA released their 2007 MHRA Device Bulletin – Safety Guidelines for Magnetic Resonance Imaging Equipment, which included ferromagnetic detection in the document’s MR Suite Recommendations section. In the MHRA document, a two-stage ferromagnetic screening process is recommended, one near the door to the MRI room for large threats and a patient screening, capable of finding even smaller threats…
“As well as reducing the likelihood of small projectile incidents, the systems are designed to reduce the likelihood of an MRI scan having to be repeated e.g. due to the presence of an object distorting the MRI scan image.”
In February of 2008 the Joint Commission added their thoughts with something of an omnibus MRI safety Sentinel Event Alert (their highest patient safety alert). The top recommendations of the SEA included access controls and enhanced screening for threats…
“Use trained personnel to screen all non-emergent patients twice, providing two separate opportunities for them to answer questions about any metal objects they may have on them, any implanted devices, drug delivery patches, tattoos, and any electrically, magnetically, or mechanically activated devices they may have… [U]se other means to determine if the patient has implants or other devices that could be negatively affected by the MRI scan (e.g., look for scars or deformities, scrutinize the patient’s history, use plain-film radiography, use ferromagnetic detectors to assist in the screening process, etc.).” [Emphasis mine.]
And most recently, earlier in July of this year, the US Veterans Administration released a sweeping revision to their MRI Design Guide which offers design input on technical, operational and safety factors for MRI suites. The new MRI Design Guide covers a LOT of material, but included in its provisions is the use of ferromagnetic detection screening for all persons approaching the MRI magnet…
“It is recommended that MRI facilities install ferromagnetic detection systems for use in screening persons and equipment entering Zones III and IV to interdict potential threat objects.” [Emphasis mine.]
For the moment, this chorus of official recommendations are not yet requirements, but that is about to change. The Joint Commission is said to be implementing a new risk-management requirement for accredited facilities which will demand that Joint Commission accredited facilities perform their own risk analysis using, as one of the criteria, the Joint Commission’s own Sentinel Event Alerts. Accredited MRI providers will need to demonstrate how it is that they provide quality-control review and redundancy of their MRI screenings.
The ACR’s MR Accreditation Committee is also entertaining a formal request to incorporate safety provisions of the ACR’s Guidance Document as a part of ACR MR Accreditation. Both the form and timeline of any changes in ACR accreditation are, as yet, unknown, but the current chair of the MR Accreditation Committee, Dr. A. Joseph Borelli, believes strongly in the principles of the Guidance Document.
So if the decision to embrace ferromagnetic detection or postpone it is influenced by what the regulatory / accrediting bodies think of it, the message is quite clear… ferromagnetic detection helps make a positive impact on patient safety and its use, at least among these four agencies, is universally called for.Tobias Gilk, President & MRI Safety Director Mednovus, Inc. Tobias.Gilk@Mednovus.com www.MEDNOVUS.com